Systems for accessing nerves within bone

ABSTRACT

System and methods are shown having a tube-within-tube assembly with a deployable curved deflectable tube or cannula that deploys from a straight cannula or trocar. The curved cannula has pre-curved distal end to create an angular range of 0° to 180° when fully deployed from the straight trocar. The curve is configured such that the flexible element carrying a treatment device can navigate through the angular range of deployment of the curved cannula. The curved cannula allows the flexible element to navigate through a curve within bone without veering off towards an unintended direction.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.12/566,895 filed on Sep. 25, 2009, which claims the benefit of U.S.Provisional Application 61/100,553 filed on Sep. 26, 2008, both of whichare expressly incorporated in their entirety by reference herein.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable

INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISC

Not Applicable

NOTICE OF MATERIAL SUBJECT TO COPYRIGHT PROTECTION

A portion of the material in this patent document is subject tocopyright protection under the copyright laws of the United States andof other countries. The owner of the copyright rights has no objectionto the facsimile reproduction by anyone of the patent document or thepatent disclosure, as it appears in the United States Patent andTrademark Office publicly available file or records, but otherwisereserves all copyright rights whatsoever. The copyright owner does nothereby waive any of its rights to have this patent document maintainedin secrecy, including without limitation its rights pursuant to 37C.F.R. §1.14.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention pertains generally to generating passageways throughtissue, and more particularly to creating curved paths in bone.

2. Description of Related Art

Recently, the technique of accessing the vertebral body throughminimally invasive means has been developed through the surgicaltechniques used in vertebroplasty and kyphoplasty. Although accessingthe vertebral segments of the spine through the pedicle and into thelateral/anterior section of the body of the vertebra is the primarymethod of placing a treatment device (e.g. a bone cement delivery deviceand/or an RF probe) into the vertebra, it is difficult to place a probein the posterior midline section of the vertebra. Furthermore, accessingthe posterior midline section of the S1 segment of the spine isdifficult with a straight linear access route. A probe preferably needsto be capable of navigating to the posterior section of the S1 vertebralbody as well as the same target area within a lumbar vertebral segment.In addition, it is contemplated that spinal segments in the cervical andthoracic spine may also be targeted.

In order to accurately and predictably place a treatment device in theposterior midline section of a lumbar vertebral body or S1 vertebralbody, the device or probe needs to navigate to said area through varyingdensities of bone. However due to the varying densities of bone, it isdifficult to navigate a probe in bone and ensure its positioning will bein the posterior midline section of the vertebral body.

Current techniques for tissue aspirations require a coaxial needlesystem that allows taking several aspirates through a guide needlewithout repositioning the guide needle. However the problem with thissystem is that after the first pass of the inner needle in to thelesion, subsequent passes tend of follow the same path within the mass,yielding only blood not diagnostic cells.

A scientific paper written by Kopecky et al., entitled “Side-ExitingCoaxial Needle for Aspiration Biopsy,” describes the use of a sideexiting coaxial needle to allow for several aspiration biopsies. Theguide needle has a side hole 1 cm from the distal tip. When a smallerneedle is advanced through this new guide needle, the smaller needle isdeflected by a ramp inside the guide, causing the smaller needle to exitthrough the side hole. Although this side exiting needle is able todeflect a bone aspiration needle, it does not guarantee that the needleexits the side hole in a linear direction into the tissue site. Once thetissue aspiration needle exits the needle, it will deviate from a linearpath depending on the density of the tissue and inherent materialstrength of the needle. This is an inherent problem the device is unableto overcome.

Accordingly, an object of the present invention is a system and methodfor generating a path in bone that predictably follows a predeterminedcurved path.

BRIEF SUMMARY OF THE INVENTION

The present invention is directed to systems and methods to deploy andnavigate a flexible treatment instrument, such as an RF bipolar probe,within bone. Although the systems and methods described below areprimarily directed to navigating bone through a vertebral member of thespine, and particularly to treat the BVN of a vertebral member, it isappreciated that the novel aspects of the present invention may beapplied to any tissue segment of the body.

The first novel principle of this invention is the ability to navigate acurve or angle within varying densities of cancellous bone and create astraight channel at the end of the navigated curve or angle. Severalsystems are described.

One aspect is a method of therapeutically treating a vertebral bodyhaving an outer cortical bone region and an inner cancellous boneregion, and a BVN having a trunk extending from the outer cortical boneregion into the inner cancellous region and a branches extending fromthe trunk to define a BVN junction, comprising the steps of: a)inserting an energy device into the vertebral body, and b) exclusivelydepositing energy within the inner cancellous bone region of thevertebral body between, but exclusive of the BVN junction and the outercortical bone region, to denervate the BVN.

In another aspect of the present invention, a tube-within-tubeembodiment has a deployable curved Nitinol tube that deploys from astraight cannula. The Nitinol tube is pre-curved to create an angularrange of approximately 0° to approximately 180°, but more specificallyfrom approximately 45° to approximately 110°, when fully deployed fromthe straight cannula. The design of the curve is such that the flexibleelement (carrying the treatment device) can navigate through the angularrange of deployment of the nitinol tube. The curved nitinol tube allowsthe flexible element to navigate through a curve within bone withoutveering off towards an unintended direction. Cancellous bone densityvaries from person to person. Therefore, creating a curved channelwithin varying density cancellous bone will generally not predictably oraccurately support and contain the treatment device as it tries tonavigate the curved channel. With the present invention, the flexibleelement is deployed into the bone through the curved Nitinol tube, whichsupports the element as it traverses through the curve. When it departsfrom the tube, it will do so in a linear direction towards the targetzone. This design allows the user to predictably and accurately deploythe flexible element towards the target zone regardless of the densityof the cancellous bone.

An aspect of the invention is a system for channeling a path into bone.The system comprises a trocar having a central channel and opening atits distal tip, and a cannula sized to be received in said centralchannel and delivered to said distal opening. The cannula has adeflectable tip with a preformed curve such that the tip straightenswhile being delivered through the trocar and regains its preformed curveupon exiting and extending past the distal opening of the trocar togenerate a curved path in the bone corresponding to the preformed curveof the deflectable tip. The cannula comprises a central passagewayhaving a diameter configured allow a treatment device to be deliveredthrough the central passageway to a location beyond the curved path.

In one embodiment, the system further includes a straight styletconfigured to be installed in the trocar, wherein the straight styletcomprises a sharp distal tip that is configured to extend beyond thedistal opening of the trocar to pierce the bone as the trocar is beingdelivered to a treatment location within the bone.

The system may further include a straightening stylet configured to beinstalled in the cannula, wherein the straightening stylet comprising arigid construction configured to straighten the distal tip of thecannula when positioned in the trocar.

In an alternative embodiment, the straightening stylet further comprisesa sharp distal end to pierce the bone, and the straightening stylet andcannula are installed in the trocar in place of the straight stylet asthe trocar is delivered into the bone.

In a preferred embodiment, the system further includes a curved stylethaving an outer radius sized to fit within the central passageway of thecurved cannula. The curved stylet is configured to be installed in thecurved cannula while the curved cannula is extended past the distalopening of the trocar, the curved stylet configured to block the distalopening of the curved cannula while being delivered into the bone.Preferably, the curved stylet has a curved distal end corresponding tothe curve of the curved cannula.

The curved stylet also has a sharp distal tip configured to extend pastthe curved cannula to pierce the bone as the cannula is delivered pastthe distal opening of the trocar. The curved stylet also preferablycomprises an angled distal tip configured to further support andmaintain the curved stylet radius as it is delivered past the distalopening of the trocar and into bone.

Preferably, the curved stylet and the curved cannula have matingproximal ends that align the curve of the curved stylet with the curveof the curved cannula.

In one embodiment, the system further includes a straight channelingstylet configured to be installed in the cannula after removing thecurved stylet, wherein the straight channeling stylet is flexiblydeformable to navigate the curved cannula yet retain a straight formupon exiting the curve cannula, and wherein straight channeling stylethas a length longer than the curved cannula such that it creates alinear path beyond the distal end of the curved cannula when fullyextended.

Another aspect is method for channeling a path into bone to a treatmentlocation in the body of a patient. The method includes the steps ofinserting a trocar having a central channel and opening at its distaltip into a region of bone at or near the treatment location, anddelivering a cannula through said central channel and to said distalopening, wherein the cannula comprises a deflectable tip with apreformed curve such that the tip straightens while being deliveredthrough the trocar and regains its preformed curve upon exiting thetrocar, and extending the cannula past the distal opening of the trocarto generate a curved path in the bone corresponding to the preformedcurve of the deflectable tip. Finally, a treatment device is deliveredthrough a central passageway in said cannula to the treatment locationbeyond the curved path.

In one embodiment, inserting a trocar into a region of bone comprisesinserting a stylet into the trocar such that the stylet extends beyondthe distal opening of the trocar, and inserting the stylet and trocarsimultaneously into the region of bone such that the stylet pierces thebone as the trocar is being delivered to a treatment location.

In another embodiment, delivering a cannula through the central channelcomprises inserting a straightening stylet into the central passagewayof the cannula, wherein the straightening stylet comprises a rigidconstruction configured to straighten the curved distal tip of thecannula, and inserting the straightening stylet and straightened cannulasimultaneously into the trocar.

In an alternative embodiment, the straightening stylet further comprisesa sharp distal end to pierce the bone, wherein the straightening styletand cannula are installed simultaneously along with the trocar as thetrocar is delivered into the bone.

In yet another embodiment, extending the cannula past the distal openingis done by inserting a curved stylet into the central passageway of thecurved cannula such that a distal tip of the curved stylet extends to atleast the distal opening of the curved cannula, and simultaneouslyextending the curved cannula and curved stylet from the distal end ofthe trocar such that the curved stylet blocks the distal opening of thecurved cannula while being delivered into the bone.

In a preferred embodiment, the curved stylet has a curved distal endcorresponding to the curve of the curved cannula, and wherein the curvedstylet reinforces the curved shape of the curved cannula as the curvedcannula is extended past the distal opening of the trocar. The curvedstylet has a sharp distal tip such that it is advanced within thecentral passageway so that the curved stylet extends past the distalopening of the curved cannula such that the curved stylet pierces thebone as the cannula is delivered past the distal opening of the trocar.

In a further step, the curved stylet is removed from the curved cannula,and a straight channeling stylet is inserted into the curved distal endof the cannula. The straight channeling stylet is flexibly deformable tonavigate the curved cannula, yet retain a straight form upon exiting thecurved cannula. The straight channeling stylet is longer than the curvedcannula to create a linear channel beyond the distal tip of the curvedcannula.

In a preferred embodiment, the trocar is inserted through a corticalbone region and into a cancellous bone region of a vertebrae, and thecurved cannula is extended though at least a portion of the cancellousbone region to a location at or near the treatment location. A preferredtreatment location comprises a BVN of the vertebrae, and treatment isdelivered to the treatment location to denervate at least a portion ofthe BVN. In one embodiment, a portion of the BVN is denervated bydelivering focused, therapeutic heating to an isolated region of theBVN. In another embodiment, a portion of the BVN comprises is denervateddelivering an agent to the treatment region to isolate treatment to thatregion. Preferably, the treatment is focused on a location of the BVNthat is downstream of one or more branches of the BVN.

Another aspect is a kit for channeling a path into bone. The kitincludes a trocar having a central channel and opening at its distaltip, and a cannula selected from a set of cannulas sized to be receivedin said central channel and delivered to said distal opening. Thecannula has a deflectable distal tip with a preformed curve such thatthe tip straightens while being delivered through the trocar and regainsits preformed curve upon exiting and extending past the distal openingof the trocar to generate a curved path in the bone corresponding to thepreformed curve of the deflectable tip. The cannula comprises a centralpassageway having a diameter configured allow a treatment device to bedelivered through the central passageway to a location beyond the curvedpath, wherein the set of cannulas comprises one or more cannulas thathave varying preformed curvatures at the distal tip.

In a preferred embodiment, the one or more cannulas have a varyingpreformed radius at the distal tip. In addition, the one or morecannulas each have distal tips that terminate at varying angles withrespect to the central channel of the trocar. The length of the distaltips may also be varied. The angle of the distal with respect to thecentral channel of the trocar may vary from 0 degrees to 180 degrees.

The kit may further include a straight stylet configured to be installedin the trocar, the straight stylet comprising a sharp distal tip that isconfigured to extend beyond the distal opening of the trocar to piercethe bone as the trocar is being delivered to a treatment location withinthe bone.

In a preferred embodiment, the kit includes a set of curved styletshaving an outer radius sized to fit within the central passageway of thecurved cannula, wherein each curved stylet is configured to be installedin the curved cannula while the curved cannula is extended past thedistal opening of the trocar. The curved stylet is configured to blockthe distal opening of the curved cannula while being delivered into thebone. Each curved stylet has a varying curved distal end correspondingto the curve of a matching curved cannula in the set of curved cannulas.The curved stylet has a sharp distal tip configured to extend past thecurved cannula to pierce the bone as the cannula is delivered past thedistal opening of the trocar.

In another embodiment, the kit includes a set of straight channelingstylets wherein one of the set of stylets is configured to be installedin the cannula after removing the curved stylet. The straight channelingstylet is flexibly deformable to navigate the curved cannula yet retaina straight form upon exiting the curve cannula. Each of the straightchanneling stylets has a varying length longer than the curved cannulasuch that the straight channeling stylet creates a predetermined-lengthlinear path beyond the distal end of the curved cannula when fullyextended.

Further aspects of the invention will be brought out in the followingportions of the specification, wherein the detailed description is forthe purpose of fully disclosing preferred embodiments of the inventionwithout placing limitations thereon.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

The invention will be more fully understood by reference to thefollowing drawings which are for illustrative purposes only:

FIG. 1 is a system for generating a curved path in bone according to thepresent invention.

FIG. 2 is a sectional view of the system of FIG. 1

FIG. 3 illustrates a sectioned view of a vertebral body with a pathbored through the cortical shell.

FIGS. 4A-F illustrate a method for accessing the BVN with the system ofthe present invention.

FIG. 5 shows an alternative system for generating a curved path in boneaccording to the present invention.

FIG. 6 shows the system of FIG. 5 being installed in a vertebral body.

FIGS. 7A-7B show a curved stylet in accordance with the presentinvention.

DETAILED DESCRIPTION OF THE INVENTION

Referring more specifically to the drawings, for illustrative purposesthe present invention is embodied in the apparatus generally shown inFIG. 1 through FIG. 7B. It will be appreciated that the apparatus mayvary as to configuration and as to details of the parts, and that themethod may vary as to the specific steps and sequence, without departingfrom the basic concepts as disclosed herein.

FIGS. 1 and 2 illustrate a first embodiment of the present inventioncomprising a system or kit 10 for forming a path through bone. Thesystem comprises a needle trocar 20 (the main body of the instrumentset). The trocar 20 comprises an elongate shaft 28 having a handle 24 atits proximal end 32 and a central lumen 36 passing through to the distalend 22 of the trocar 20. The central lumen 36 is generally sized toallow the other instruments in the system 10 to be slideably introducedinto the patient to a treatment region. System 10 further comprises astraight stylet 80 having a sharp-tipped needle 84 at its distal endthat is used with the needle trocar 20 to create the initial paththrough the soft tissue and cortical shell to allow access to thecancellous bone, a curved cannula 50 that is used to create/maintain thecurved path within the bone/tissue. A straightening stylet 40 is used tostraighten out the curve and load the curved cannula 50 into the needletrocar 20. A curved stylet 60 is used in conjunction with the curvedcannula 50 to create the curved path within the bone/tissue, and achanneling stylet 90 is used to create a working channel for a treatmentdevice (such as RF probe 100) beyond the end of the curved path createdby the curved cannula 50.

The surgical devices and surgical systems described may be used todeliver numerous types of treatment devices to varying regions of thebody. Although the devices and systems of the present invention areparticularly useful in navigating through bone, it is appreciated thatthey may also be used to navigate through soft tissue, or throughchannels or lumens in the body, particularly where one lumen may branchfrom another lumen.

The following examples illustrate the system 10 applied to generating acurve bone path in the vertebral body, and more particularly forcreating a bone path via a transpedicular approach to access targetedregions in the spine. In particular, the system 10 may be used todeliver a treatment device to treat or ablate intraosseous nerves, andin particular that basivertebral nerve (BVN). Although the system andmethods provide significant benefit in accessing the BVN, it isappreciated that the system 10 of the present invention may similarly beused to create a bone path in any part of the body.

FIG. 3 illustrates a cross-sectional view of a vertebra 120. Recently,the existence of substantial intraosseous nerves 122 and nerve branches130 within human vertebral bodies (“basivertebral nerves”) have beenidentified. The basivertebral nerve 122 has at least one exit 142 pointat a location along the nerve 122 where the nerve 122 exits thevertebral body 126 into the vertebral foramen 132.

Preferably, the basivertebral nerves are at, or in close proximity to,the exit point 142. Thus, the target region of the BVN 122 is locatedwithin the cancellous portion 124 of the bone (i.e., to the interior ofthe outer cortical bone region 128), and proximal to the junction J ofthe BVN 122 having a plurality of branches 130 (e.g. between points Aand B along nerve 122). Treatment in this region is advantageous becauseonly a single portion of the BVN 122 need be effectively treated todenervate or affect the entire system. Typically, treatment inaccordance with this embodiment can be effectuated by focusing in theregion of the vertebral body located between 60% (point A) and 90%(point B) of the distance between the anterior and posterior ends of thevertebral body. In contrast, treatment of the BVN 122 in locations moredownstream than the junction J require the denervation of each branch130.

In one approach for accessing the BVN, the patient's skin is penetratedwith a surgical instrument which is then used to access the desiredbasivertebral nerves, i.e., percutaneously. In one embodiment, atranspedicular approach is used for penetrating the vertebral cortex toaccess the BVN 122. A passageway 140 is created between the transverseprocess 134 and spinous process 136 through the pedicle 138 into thecancellous bone region 124 of the vertebral body 126 to access a regionat or near the base of the nerve 122. It is appreciated that apostereolateral approach (not shown) may also be used for accessing thenerve.

FIGS. 4A-F illustrate a preferred method for accessing the BVN with thesystem 10 of the present invention. First, the straight stylet 80 isinserted in aperture 26 at the proximal end 32 of needle trocar 20. Thestraight stylet 80 is advanced down the central lumen 36 (see FIG. 2) ofthe trocar 20 until the proximal stop 82 abuts against handle 24 of thetrocar 20, at which point the distal tip 84 of straight stylet protrudesout of the distal end 22 of the trocar 20. The tip 84 of the straightstylet 80 preferably comprises a sharp tip for piercing soft tissue andbone.

Referring now to FIG. 4A, the assembly (trocar 20 and straight stylus80) is advanced through soft tissue to the surface of the bone. Once theproper alignment is determined, the assembly is advanced through thecortical shell of pedicle 138 and into the cancellous interior 124 ofthe bone.

After the proper depth is achieved, the straight stylet 80 is removedfrom the trocar 20, while the trocar 20 remains stationary within thevertebrae 120. The straightening stylet 40 is inserted into proximalaperture 53 (see FIG. 2) of the curved cannula 50 and advanced along thecentral lumen of the curved cannula 50 until the stop 42 of the stylet40 abuts up to the proximal end 52 of the curved cannula. This forcesthe distal tip of the straight stylet through the curved section 56 ofthe curved cannula 50 to straighten out the curved section 56. It iscontemplated that the straight stylet comprise a hard, non-compliantmaterial and the distal end of the curved cannula 50 a compliant, yetmemory retaining material (e.g. Nitinol, formed PEEK, etc.) such thatthe curved section 56 yields to the rigidity of the straightening stylet40 when installed, yet retains its original curved shape when the stylet40 is removed.

As shown in FIG. 4B, once the straightening stylet 40 is secure and thecurved cannula 50 is straight, they are inserted into the needle trocar20 and secured. Proper alignment (e.g. prevent rotation, orient curvedirection during deployment) is maintained by aligning a flat on theupper portion 58 of the curved cannula 50 to an alignment pin securedperpendicularly into the needle trocar 20 handle 24. Once the curvedcannula 50 is secure, the straightening stylet 40 is removed, while thecurved cannula 50 remains stationary within the trocar 20.

Referring to FIG. 4C, the curved stylet 60 is then straightened out bysliding the small tube 68 proximally to distally on its shaft towardsthe distal tip 64 or from the distal tip 64 proximally on its shafttowards the proximal end 62. Once the curved distal tip 66 isstraightened out and fully retracted inside the small tube 68, thecurved stylet 60 is inserted into the proximal aperture 53 of the curvedcannula 50, which still resides inside the needle trocar 20. As thecurved stylet 60 is advanced into the curved cannula 50, the small tube68 is met by a stop 55 (see FIG. 4C). As the curved stylet 60 continuesto advance the small tube 68 is held inside the handle of the curvedcannula 50. This allows the curve of the stylet 60 to be exposed insidethe curved cannula 50. To create the maximum force the curve of the twoparts (50 & 60) must be aligned. To ensure alignment the cap on thecurved stylet 60 has an alignment pin 70 which engages with an alignmentnotch on the proximal end 52 of the curved cannula 50.

Once the stylet 60 is fully seated and aligned with the curved cannula50 the tip of the curved stylet 60 will protrude from the tip of thecurved cannula 50 by about 1/16 to 3/16 inches. This protrusion willhelp to drive the curve in the direction of its orientation duringdeployment.

Referring now to FIG. 4D, with the curved stylet 60 and the curvedcannula 50 engaged, the locking nut 58 at the top of the curved cannula50 is rotated counter clockwise to allow the cannula 50 and curvedstylet 60 to be advanced with relation to the needle trocar 20 such thatthe proximal end 52 abuts against 58, advancing the curved cannula 50and curved stylet 60 beyond the distal opening of trocar 20 to generatea curved path in the cancellous bone region 124. As the curved cannula50 and curved stylet 60 are advanced they will preferably curve at aradius of 0.4 to 1.0 inches through cancellous bone and arc to an anglebetween 5 and 110 degrees. Once the curved cannula 50 and curved stylet60 are deployed to the intended angle, the locking nut at the top of thecurved cannula 50 is engaged with the needle trocar 20 to stop anyadditional advancement of the curved stylet cannula assembly.

FIGS. 7A-7B illustrate the tip of the curved stylet 60, which has beenformed with two angles. To help the curve deployment in the properdirection the curved section 66 of the curved stylet 60 is shaped in apredetermined orientation. The angle on the inside of the curve 72 isless than the angle on the outside of the curve 74. This disparity inangle helps the stylet cannula assembly 50 & 60 curve in the bone asbone pushes against outside curve face 74 ensuring the curve radius ismaintained during deployment.

Referring now to FIG. 4E, the curved stylet 60 is then removed andreplaced by the channeling stylet 90. The tip 94 of the channelingstylet 90 is advanced beyond the end 54 of the curved cannula 50 towardsthe intended target treatment zone.

Referring now to FIG. 4F, once the channeling stylet 90 reaches thetarget treatment zone, it is removed creating a working channel 146.Channel 140 will generally have a first section 142 that crosses thecortical bone of the pedicle 138, followed by a curved path 144. Thesesections are occupied by curved cannula 50 such that a treatment devicefed through the cannula 50 will have to follow the curve of the cannula50 and not veer off in another direction. The channel may furthercomprise the linear extension 146 in the cancellous bone 124 to furtheradvance the treatment device toward the treatment site T.

With the trocar 20 and curved cannula 50 still in place, a treatmentdevice (e.g. treatment probe 100 shown in FIG. 2, with an active element102 on the distal end 104 of elongate flexible catheter 110 is deliveredto the target treatment location T to perform a localized treatment.

In a preferred embodiment, the active element 102 is delivered to thetreatment site and activated to delivery therapeutic treatment energy.The treatment probe may comprise an RF delivery probe having bipolarelectrodes 106 and 108 that deliver a therapeutic level of heating tostimulate or ablate the nerve 122.

It is appreciated that any number of treatment modalities may bedelivered to the treatment site for therapeutic treatment. For example,treatment may be affected by monopolar or tripolar RF, ultrasound,radiation, steam, microwave, laser, or other heating means.Additionally, the treatment device may comprise a fluid deliverycatheter that deposits an agent, e.g. bone cement, or other therapeuticagent, to the treatment site T. Alternatively, cryogenic cooling may bedelivered for localized treatment of the BVN. Furthermore, treatment maybe affected by any mechanical destruction and or removal means capableof severing or denervating the BVN. For example, a cutting blade, bur ormechanically actuated cutter typically used in the art of orthoscopicsurgery may be used to affect denervation of the BVN.

In addition to or separate from treating the BVN, a sensor may bedelivered to the region to preoperatively or postoperatively measurenerve conduction at the treatment region. In this configuration, thesensor may be delivered on a distal tip of a flexible probe that may ormay not have treatment elements as well.

The goal of the treatment may be ablation, or necrosis of the targetnerve or tissue, or some lesser degree of treatment to denervate theBVN. For example, the treatment energy or frequency may be justsufficient to stimulate the nerve to block the nerve from transmittingsignal (e.g. signals indicating pain).

Once the treatment is complete, the probe 100 is withdrawn. The curvedcannula 50 is then withdrawn into the needle trocar 20. The needletrocar 20 with the curved cannula 50 is then removed and the access siteis closed as prescribed by the physician.

In the above system 10, the design of the curved sections 56 and 66 ofthe curved cannula 50 and curved stylet 60, respectively, is such thatthe flexible element (e.g. carrying the treatment device) can navigatethrough the angular range of deployment of the Nitinol tube of thecurved cannula 50. The curved nitinol tube of the curved cannula 50allows the flexible element to navigate through a curve within bonewithout veering off towards an unintended direction. Cancellous bonedensity varies from person to person. Therefore, creating a curvedchannel within varying density cancellous bone 124 will generally notpredictably or accurately support and contain the treatment device as ittries to navigate the curved channel.

With the system 10 of the present invention, the treatment device 100 isdeployed into the bone through the curved Nitinol tube of the curvedcannula 50, which supports the element as it traverses through thecurve. When it departs from the tube, it will do so in a lineardirection along path 146 towards the target zone. This allows the userto predictably and accurately deploy the treatment device towards thetarget zone T regardless of the density of the cancellous bone.

In some embodiments, a radius of curvature that is smaller than thatwhich can be achieved with a large diameter Nitinol tube may beadvantageous. To achieve this, the curved tube of the curved cannula 50may take one of several forms. In one embodiment, the tube 50 is formedfrom a rigid polymer that can be heat set in a particular curve. If thepolymer was unable to hold the desired curve, an additional stylet (e.g.curved stylet 60) of Nitinol, or other appropriate material, may also beused in conjunction with the polymer tube to achieve the desired curve.This proposed combination of material may encompass and number orvariety of materials in multiple different diameters to achieve thedesired curve. These combinations only need to ensure that the finaloutside element (e.g. trocar 20) be “disengageable” from the internalelements and have an inner diameter sufficient to allow the desiredtreatment device 100 to pass to the treatment region T.

In an alternative embodiment, of the curved cannula 50 may comprise aNitinol tube having a pattern of reliefs or cuts (not shown) in the wallof the tube (particularly on the outer radius of the bend). The patternof cuts or reliefs would allow the tube to bend into a radius tighterthan a solid tube could without compromising the integrity of the tubingwall.

FIG. 5 illustrates a second embodiment of the system or kit 200 of thepresent invention that may be used to reduce the number of stepsrequired for the procedure. The second embodiment includes a needletrocar 20, straightening stylet 40, used with the needle trocar 20 andthe curved cannula 50 to create the initial path through the soft tissueand cortical shell to allow access to the cancellous bone, curved stylet60 used in conjunction with the curved cannula 50 to create the curvedpath within the bone/tissue, and channeling stylet 90 used to create aworking channel for the probe beyond the end of the curved path createdby the curved stylet.

In one method according to the present invention, the straighteningstylet 40 is inserted into the curved cannula 50 and secured. In thisembodiment, the straightening stylet 40 has a sharp tip 46 designed topenetrate bone. Once the straightening stylet 40 is secure and thecurved cannula 50 is straight, they are inserted into the needle trocar20 and secured. In this embodiment, the curved cannula 50 andstraightening stylet 40 are inserted into the shaft 28 of the trocar 20only as far as to have sharp tip 46 of the straightening stylet 40protrude from the distal end 22 of the trocar 20. Proper alignment ismaintained by aligning a flat on the upper portion of the curved cannula50 with a pin secured perpendicularly into the needle trocar 20 handle.

Referring now to FIG. 6, once the curved cannula 50 is secure, theassembly (trocar 20, curved cannula 50, and straightening stylet 40) isadvanced through soft tissue to the surface of the bone. After findingthe proper alignment at the pedicle 138 of vertebrae 120, the assembly(trocar 20, curved cannula 50, and straightening stylet 40) is advancedthrough the cortical shell 128 and into the cancellous interior 124 ofthe bone.

After the proper depth is achieved, the straightening stylet 40 isremoved. The curved stylet 60 is then straightened out by sliding thesmall tube 68 on its shaft towards the distal tip 64. The curved distaltip 66 is straightened out and fully retracted inside the small tube 68,and then the curved stylet 60 is inserted into the curved cannula 50which still resides inside the needle trocar 20. Once the curved stylet60 is inserted into the curved cannula 50, the small tube 68 is met by astop 55 (see FIG. 4C). As the curved stylet 60 continues to advance, thesmall tube 68 is held inside the handle of the curved cannula 50. Thisallows the curve of the stylet 60 to be exposed inside the curvedcannula 50.

To create the maximum force, it is preferred that the curve of the twoparts (50 & 60) are aligned. To ensure alignment the cap on the curvedstylet 60 has an alignment pin, which engages with a notch on the top ofthe curved cannula 50.

When the stylet 60 is fully seated and aligned with the curved cannula50, the tip of the curved stylet 60 will protrude from the tip of thecurved cannula 50 by about 1/16 to 3/16 inches. This protrusion willhelp to drive the curved cannula 50 in the direction of its orientationduring deployment. Once the curved stylet 60 and the curved cannula 50are engaged, the lock nut at the top of the curved cannula 50 is rotatedcounter clockwise to allow the cannula 50 and stylet 60 to be advancedwith relation to the needle trocar 20 (as shown in FIG. 4D). As thecurved cannula and stylet are advanced they generate a curved pathtoward the treatment location T. Once the curved cannula 50 and stylet60 are deployed to the intended angle, the lock nut at the top of thecurved cannula 50 is engaged with the needle trocar 20 to stop anyadditional advancement of the curved stylet cannula assembly.

The curved stylet 60 is then removed and replaced by the channelingstylet 90. The channeling stylet 90 is advanced beyond the end of thecurved cannula 50 (see FIG. 4E) towards the intended target treatmentzone creating a working channel for the active element to be inserted.Once the channeling stylet 80 reached the target treatment zone it isremoved and replaced by the treatment device 100, which is delivered tothe treatment site T and activated.

Once the treatment is complete, the treatment device 100 is withdrawn.The curved cannula 50 is then withdrawn into the needle trocar 20. Theneedle trocar 20 with the curved cannula 50 is then removed and theaccess site is closed as prescribed by the physician.

FIGS. 7A and 7B illustrate detail views of a Nitinol wire for the curvedstylet 60 (proximal end not shown). The wire comprises a shaft 78 havingconstant diameter D and a length L_(s) that may vary according to theapplication and desired depth to the treatment location. The wire has apreformed distal tip that is curved to have a radius r that redirectsthe distal tip 64 at an angle Θ with the shaft. As shown in FIG. 7A,angle Θ is shown to be approximately 110°. However, it is appreciatedthat the preformed tip may have an angle ranging from a few degrees(slight deflection off axis), to up to 180° (e.g. directing back towardthe proximal end).

As shown in FIG. 7B detailing the distal tip 64, the tip may have adistal extension L_(T) that extends away from the shaft 78. To promotechanneling along a path that follows radius r, the distal tip 64 isconfigured with a dual-plane bevels 74 and 72. Plane 74 is offset atangle β, and plane 72 is offset at angle α. This configuration of theleading—allows for the stylet and/or curved cannula to travel throughbone in a path correlating to the specified curve in the stylet and/orcannula.

In the example illustrated in FIGS. 7A and 7B, the curved stylet 60 hasa shaft length L_(s) of approximately 3.6 in., diameter D ofapproximately 0.040 in., and a distal tip length L_(T) of 0.125 in.,radius r of 0.40 in., and angle β=35° and angle α=31°. It should benoted that the above dimensions are for illustration only, and may varydepending on the anatomy an tissue type.

It is appreciated that all the above embodiments may be provided as akit of instruments to treat different regions of the body. For example,the location, orientation and angle of the treatment device with respectto the trocar 20 may be varied by providing a set of instruments atvarying increments. This may be achieved by varying the curvature (56,66) in the curved cannula 50 and curved stylet 60. The curvature may bevaried by varying the radius of curvature r, the insertion depth (shaftlength L_(s) and tip length L_(T), and/or the final exit angle Θ withrespect to the trocar 20 central bore. Thus, the physician may select adifferent kit for treating a lumber spine segment as opposed to acervical spine segment, as the anatomy will dictate the path that needsto be channeled.

Thus, when treating different spine segments, a set out of the kit maybe selected to match the vertebra (or other region being treated). Forexample, delivering the treatment device at or near the BVN junction fora lumbar vertebra may have a different angle than for a cervicalvertebra, and may vary from patient to patient. The set may be selectedfrom the kit intra-operatively, or from a pre-surgery diagnosticevaluation (e.g. radiographic imaging of the target region).

It is appreciated that each of the instruments in the embodiments 100and 200 detailed above may have any length, shape, or diameter desiredor required to provide access to the treatment region (e.g. intraosseousnerve trunk) thereby facilitating effective treatment of the targetregion. For example, the size of the intraosseous nerve to be treated,the size of the passageway in the bone (e.g. pedicle 138) for accessingthe intraosseous nerve, and the location of the bone, and thus theintraosseous nerve, are factors that that may assist in determining thedesired size and shape of the individual instruments.

The systems 100, 200 described above may be used with a number ofdifferent treatment modalities for therapeutic treatment of the targetregion. For example, in one embodiment, it is desirable to operate thetreatment device 100 in a manner that ablates the tissue of the targetregion (e.g. BVN) to produce as described in U.S. Pat. No. 6,699,242,herein incorporated by reference in its entirety.

In another embodiment, the treatment device is configured to delivertherapeutic treatment that is targeted to block nerve conduction withoutablating the nerve, i.e. thermal treatment is delivered to the nerve(e.g. via thermal therapy, agent or the like) that results indenervation of the BVN without necrosis of tissue. This may be achievedvia delivery of a lesser amount of energy or agent to the tissue site(either in the form of less exposure time, concentration, intensity,etc.) than is required for ablation, but an amount sufficient to achievesome amount of temporary or permanent denervation.

As can be seen, therefore, the present invention includes the followinginventive embodiments among others:

1. A system for channeling a path into bone, comprising: a trocar havinga central channel and opening at its distal tip; and a curved cannulasized to be received in said central channel and delivered to saiddistal opening; the curved cannula having a deflectable tip with apreformed curve such that the tip straightens while being deliveredthrough the trocar and regains its preformed curve upon exiting andextending past the distal opening of the trocar to generate a curvedpath in the bone corresponding to the preformed curve of the deflectabletip; wherein the curved cannula comprises a central passageway having adiameter configured allow a treatment device to be delivered through thecentral passageway to a location beyond the curved path.

2. A system as recited in embodiment 2, further comprising: a straightstylet configured to be installed in the trocar; the straight styletcomprising a sharp distal tip that is configured to extend beyond thedistal opening of the trocar to pierce the bone as the trocar is beingdelivered to a treatment location within the bone.

3. A system as recited in embodiment 2, further comprising: astraightening stylet configured to be installed in the curved cannula;the straightening stylet comprising a rigid construction configured tostraighten the distal tip of the curved cannula when positioned in thetrocar.

4. A system as recited in embodiment 3, wherein the straightening styletfurther comprises a sharp distal end to pierce the bone; and wherein thestraightening stylet and curved cannula are configured to be installedin the trocar in place of the straight stylet as the trocar is deliveredinto the bone.

5. A system as recited in embodiment 1, further comprising: a curvedstylet having an outer radius sized to fit within the central passagewayof the curved cannula; wherein the curved stylet is configured to beinstalled in the curved cannula while the curved cannula is extendedpast the distal opening of the trocar, the curved stylet configured toblock the distal opening of the curved cannula while being deliveredinto the bone.

6. A system as recited in embodiment 5, wherein the curved stylet has acurved distal end corresponding to the curve of the curved cannula.

7. A system as recited in embodiment 5, wherein the curved stylet has asharp distal tip configured to extend past the curved cannula to piercethe bone as the cannula is delivered past the distal opening of thetrocar.

8. A system as recited in embodiment 7, wherein the curved stylet andthe curved cannula have mating proximal ends that align the curve of thecurved stylet with the curve of the curved cannula.

9. A system as recited in embodiment 5, further comprising a straightchanneling stylet configured to be installed in the cannula afterremoving the curved stylet; wherein the straight channeling stylet isflexibly deformable to navigate the curved cannula yet retain a straightform upon exiting the curve cannula; wherein straight channeling stylethas a length longer than the curved cannula such that it creates alinear path beyond the distal end of the curved cannula when fullyextended.

10. A method for channeling a path into bone to a treatment location inthe body of a patient, comprising: inserting a trocar into a region ofbone near the treatment location; the trocar having a central channeland opening at its distal tip; and delivering a cannula through saidcentral channel and to said distal opening; wherein the cannulacomprises a deflectable tip with a preformed curve such that the tipstraightens while being delivered through the trocar and regains itspreformed curve upon exiting the trocar; extending the cannula past thedistal opening of the trocar to generate a curved path in the bonecorresponding to the preformed curve of the deflectable tip; deliveringa treatment device through a central passageway in said cannula havingto the treatment location beyond the curved path.

11. A method as recited in embodiment 10, wherein inserting a trocarinto a region of bone comprises inserting a stylet into the trocar suchthat the stylet extends beyond the distal opening of the trocar; andinserting the stylet and trocar simultaneously into the region of bonesuch that the stylet pierces the bone as the trocar is being deliveredto a treatment location.

12. A method as recited in embodiment 10, wherein delivering a cannulathrough the central channel comprises: inserting a straightening styletinto the central passageway of the cannula; the straightening styletcomprising a rigid construction configured to straighten the curveddistal tip of the cannula; and inserting the straightening stylet andstraightened cannula simultaneously into the trocar.

13. A method as recited in embodiment 12, wherein the straighteningstylet further comprises a sharp distal end to pierce the bone; andwherein the straightening stylet and cannula are installedsimultaneously along with the trocar as the trocar is delivered into thebone.

14. A method as recited in embodiment 10, wherein extending the cannulapast the distal opening comprises: inserting a curved stylet into thecentral passageway of the curved cannula such that a distal tip of thecurved stylet extends to at least the distal opening of the curvedcannula; simultaneously extending the curved cannula and curved styletfrom the distal end of the trocar such that the curved stylet blocks thedistal opening of the curved cannula while being delivered into thebone.

15. A method as recited in embodiment 14, wherein the curved stylet hasa curved distal end corresponding to the curve of the curved cannula;and wherein the curved stylet reinforces the curved shape of the curvedcannula as the curved cannula is extended past the distal opening of thetrocar.

16. A method as recited in embodiment 14, wherein the curved stylet hasa sharp distal tip; wherein curved stylet is advanced within the centralpassageway so that the curved stylet extends past the distal opening ofthe curved cannula such that the curved stylet pierces the bone as thecannula is delivered past the distal opening of the trocar.

17. A method as recited in embodiment 14, further comprising: removingthe curved stylet from the curved cannula; inserting a straightchanneling stylet into the curved distal end of the cannula; wherein thestraight channeling stylet is flexibly deformable to navigate the curvedcannula yet retain a straight form upon exiting the curved cannula;wherein the straight channeling stylet is longer than the curved cannulato create a linear channel beyond the distal tip of the curved cannula.

18. A method as recited in embodiment 10, wherein the trocar is insertedthrough a cortical bone region and into a cancellous bone region of avertebrae, and wherein the curved cannula is extended though at least aportion of the cancellous bone region to a location at or near thetreatment location.

19. A method as recited in embodiment 18, wherein the treatment locationcomprises a BVN of the vertebrae, the method further comprising:delivering treatment to the treatment location to denervate at least aportion of the BVN.

20. A method as recited in embodiment 19, wherein denervating a portionof the BVN comprises delivering focused, therapeutic heating to anisolated region of the BVN.

21. A method as recited in embodiment 19, wherein denervating a portionof the BVN comprises delivering an agent to the treatment region toisolate treatment to that region.

22. A method as recited in embodiment 19, wherein the treatment isfocused on a location of the BVN that is downstream of one or morebranches of the BVN.

23. A kit for channeling a path into bone, comprising: a trocar having acentral channel and opening at its distal tip; and a cannula selectedfrom a set of cannulas sized to be received in said central channel anddelivered to said distal opening; the cannula having a deflectabledistal tip with a preformed curve such that the tip straightens whilebeing delivered through the trocar and regains its preformed curve uponexiting and extending past the distal opening of the trocar to generatea curved path in the bone corresponding to the preformed curve of thedeflectable tip; wherein the cannula comprises a central passagewayhaving a diameter configured allow a treatment device to be deliveredthrough the central passageway to a location beyond the curved path;wherein the set of cannulas comprises one or more cannulas that havevarying preformed curvatures at the distal tip.

24. A kit as recited in embodiment 23, wherein the one or more cannulashave a varying preformed radius at the distal tip.

25. A kit as recited in embodiment 23, wherein the one or more cannulaseach have distal tips that terminate at varying angles with respect tothe central channel of the trocar.

26. A kit as recited in embodiment 25, wherein the angle of the distaltip with respect to the central channel of the trocar varies fromapproximately 45° to approximately 110°.

27. A kit as recited in embodiment 23, further comprising: a straightstylet configured to be installed in the trocar; the straight styletcomprising a sharp distal tip that is configured to extend beyond thedistal opening of the trocar to pierce the bone as the trocar is beingdelivered to a treatment location within the bone.

28. A kit as recited in embodiment 23, further comprising: a set ofcurved stylets having an outer radius sized to fit within the centralpassageway of the curved cannula; wherein each curved stylet isconfigured to be installed in the curved cannula while the curvedcannula is extended past the distal opening of the trocar; wherein thecurved stylet configured to block the distal opening of the curvedcannula while being delivered into the bone; and wherein each curvedstylet has a varying a curved distal end corresponding to the curve of amatching curved cannula in the set of curved cannulas.

29. A kit as recited in embodiment 28, wherein the curved stylet has asharp distal tip configured to extend past the curved cannula to piercethe bone as the cannula is delivered past the distal opening of thetrocar.

30. A kit as recited in embodiment 28, wherein the curved stylet and thecurved cannula have mating proximal ends that align the curve of thecurved stylet with the curve of the curved cannula.

31. A kit as recited in embodiment 28, further comprising a set ofstraight channeling stylets; wherein one of the set of stylets isconfigured to be installed in the cannula after removing the curvedstylet; wherein the straight channeling stylet is flexibly deformable tonavigate the curved cannula yet retain a straight form upon exiting thecurve cannula; wherein each of the straight channeling stylets has avarying length longer than the curved cannula such that the straightchanneling stylet creates a predetermined-length linear path beyond thedistal end of the curved cannula when fully extended.

Although the description above contains many details, these should notbe construed as limiting the scope of the invention but as merelyproviding illustrations of some of the presently preferred embodimentsof this invention. Therefore, it will be appreciated that the scope ofthe present invention fully encompasses other embodiments which maybecome obvious to those skilled in the art, and that the scope of thepresent invention is accordingly to be limited by nothing other than theappended claims, in which reference to an element in the singular is notintended to mean “one and only one” unless explicitly so stated, butrather “one or more.” All structural, chemical, and functionalequivalents to the elements of the above-described preferred embodimentthat are known to those of ordinary skill in the art are expresslyincorporated herein by reference and are intended to be encompassed bythe present claims. Moreover, it is not necessary for a device or methodto address each and every problem sought to be solved by the presentinvention, for it to be encompassed by the present claims. Furthermore,no element, component, or method step in the present disclosure isintended to be dedicated to the public regardless of whether theelement, component, or method step is explicitly recited in the claims.No claim element herein is to be construed under the provisions of 35U.S.C. 112, sixth paragraph, unless the element is expressly recitedusing the phrase “means for.”

What is claimed is:
 1. A system for channeling a path into bone,comprising: a trocar having a central channel and opening at its distaltip; and a curved cannula sized to be received in said central channeland delivered to said distal opening; the curved cannula having adeflectable tip with a preformed curve such that the tip straightenswhile being delivered through the trocar and regains its preformed curveupon exiting and extending past the distal opening of the trocar togenerate a curved path in the bone corresponding to the preformed curveof the deflectable tip; wherein the curved cannula comprises a centralpassageway having a diameter configured allow a treatment device to bedelivered through the central passageway to a location beyond the curvedpath.